Question 1

Examples of conditions that cause right-to-left shunts include all except which of the following?

Accepted Answer

Pulmonary embolism is a condition that causes a blockage in the pulmonary artery, which carries blood from the heart to the lungs. This blockage can lead to a decrease in blood flow to the lungs, which can cause a right-to-left shunt. However, acute respiratory distress syndrome, pulmonary edema, and pulmonary fibrosis are all conditions that can cause an increase in blood flow to the lungs, which can lead to a left-to-right shunt.

Question 2

Which of the following conditions causes a reduction in ventilation and results in a V/Q mismatch?

Accepted Answer

A

Question 3

A patient is admitted to the emergency room in acute pulmonary edema.The physician asks for your opinion in treating this patient.Which of the following would you recommend?

Accepted Answer

Oxygen therapy with continuous positive airway pressure (CPAP) is the best choice for treating acute pulmonary edema. CPAP delivers a constant pressure that helps keep the airways and alveoli open, decreasing the work of breathing and improving oxygenation. Nitric oxide therapy is used in the treatment of pulmonary hypertension and some types of respiratory failure, but it is not indicated in acute pulmonary edema. Helium/oxygen with a nonrebreathing mask is used in the treatment of severe upper airway obstruction, but it is not indicated in acute pulmonary edema. Oxygen therapy with an air-entrainment mask may be used in some cases, but it does not provide the same level of support as CPAP.

Question 4

Ventilatory depression that causes hypoxemia results from which of the following?

Accepted Answer

Ventilatory depression causes hypoventilation, leading to an increase in CO2 and a decrease in oxygenation, which is known as hypoxemia. This can occur due to various reasons such as sedation, opioid use, or respiratory muscle weakness, leading to alveolar hypoventilation. A right-to-left shunt is a condition where deoxygenated blood bypasses the lungs and enters the systemic circulation, leading to hypoxemia. A V/Q mismatch is a condition where there is an imbalance between ventilation and perfusion, leading to hypoxemia. A low level of atmospheric oxygen may also lead to hypoxemia, but it is not related to ventilatory depression.

Question 5

The process of hemoglobin releasing oxygen at the tissue level is referred to as:

Accepted Answer

Hemoglobin releasing oxygen at the tissue level is part of internal respiration, which refers to the exchange of gases (oxygen and carbon dioxide) between the systemic capillaries and the body tissues. Ventilation refers to the movement of air in and out of the lungs, while respiration can refer to both ventilation and gas exchange. External respiration refers to the exchange of gases between the alveoli in the lungs and the pulmonary capillaries.

Question 6

You are called to the emergency room to administer oxygen to a patient who is being treated for drug overdose.You notice that the patient's respiratory rate is six breaths per minute and that he is breathing very shallowly.This patient is ordered oxygen therapy to treat which of the following types of hypoxia?

Accepted Answer

Hypoxemic hypoxia is caused by a decrease in the oxygen-carrying capacity of the blood. In this case, the patient's shallow breathing and low respiratory rate are leading to a decrease in oxygen saturation in the blood, making it difficult for the body to deliver oxygen to the tissues. Administering oxygen therapy can help increase the oxygen saturation levels and treat hypoxemic hypoxia. Anemic hypoxia is caused by a decrease in the number of red blood cells, which reduces the oxygen-carrying capacity of the blood. Circulatory hypoxia occurs when there is a decrease in blood flow, limiting the amount of oxygen delivered to the tissues. Demand hypoxia occurs when there is an increased demand for oxygen, which cannot be met due to reduced oxygen-carrying capacity or reduced oxygen availability.

Question 7

You receive an order for oxygen therapy for a patient who has just been admitted to the CCU.Before setting up the patient's oxygen,you review her chart and find that her admitting diagnosis is decreased cardiac output secondary to heart failure.This patient is ordered oxygen therapy to treat which of the following types of hypoxia?

Accepted Answer

Circulatory hypoxia, also known as stagnant hypoxia, occurs when there is inadequate circulation of blood, as seen in heart failure. This condition leads to insufficient oxygen supply to tissues despite normal oxygen saturation and hemoglobin levels.

Question 8

Which of the following conditions causes a reduction in perfusion and results in a V/Q mismatch?

Accepted Answer

Pulmonary embolism is a blockage in the pulmonary arteries, which reduces blood flow to the lungs and causes a V/Q mismatch. Pneumonia, lung cancer, and emphysema can all affect gas exchange, but they do not necessarily cause a V/Q mismatch.

Question 9

The range of PaO₂ that is classified as moderate hypoxemia is:

Accepted Answer

According to the classification of hypoxemia based on PaO2 levels, moderate hypoxemia range from 40 to 59 mmHg.

Question 10

A 70-year-old patient diagnosed with bilateral pneumonia is admitted from a nursing home.Arterial blood gases indicate a mild hypoxemia,and her chest film shows consolidation in both lower lobes.Her respirations are stable and she has a normal breathing pattern.The physician would like to give her a low concentration of oxygen.Which of the following devices would you recommend?

Accepted Answer

A nasal cannula is the most appropriate device for a patient with mild hypoxemia and stable respirations. It provides low concentration oxygen, ranging from 24% to 44%, and is well-tolerated by patients. A simple mask, air-entrainment mask, and nonrebreathing mask are used for patients with more severe hypoxemia or unstable respirations.

Question 11

You are called to the ER to see a 37-year-old female with multiple trauma from a car accident.The physician asks that you give her oxygen with as high an FIO₂ as you can provide.Which of the following devices would you select?

Accepted Answer

A nonrebreathing mask can provide the highest FIO₂ of the options by delivering oxygen through a reservoir bag and one-way valve, preventing the rebreathing of exhaled air and ensuring a higher concentration of oxygen is inspired. This is important in the management of trauma patients who may have compromised lung function and require high levels of oxygenation.

Question 12

A patient with a tracheostomy is weaned successfully from the ventilator and is now breathing spontaneously but needs supplemental oxygen.His arterial blood gases were within normal limits,with an FIO₂ of 40% on the ventilator.Which of the following devices would you recommend?

Accepted Answer

A large-volume nebulizer with a tracheostomy collar is the appropriate choice for a patient with a tracheostomy who requires supplemental oxygen. This device is specifically designed to deliver humidified oxygen directly to the tracheostomy, ensuring that the patient receives the necessary oxygenation efficiently.

Question 13

Hyperbaric oxygen is used to treat all except which of the following conditions?

Accepted Answer

Hyperbaric oxygen therapy is not typically used to treat COPD. It is most commonly used to treat conditions such as carbon monoxide poisoning, decompression sickness, air embolism, and certain types of infections.

Question 14

A known COPD patient comes into the ER in acute distress due to bronchospasm.The patient is moderately hypoxemic,with a respiratory rate of 32.The physician would like him to have oxygen with a device that will deliver a precise FIO₂.Which of the following would you recommend?

Accepted Answer

An air-entrainment mask would be the best choice because it allows for precise delivery of a specific FIO2, which is important in the treatment of acute respiratory distress. A nasal cannula and simple mask may not provide enough oxygen for a patient who is hypoxemic, while a non-rebreathing mask may deliver too high of a FIO2 and potentially cause oxygen toxicity.

Question 15

An example of a condition that results in anemic hypoxia is:

Accepted Answer

Carbon monoxide poisoning leads to anemic hypoxia because it binds to hemoglobin with high affinity, reducing the blood's oxygen-carrying capacity.

Question 16

An example of a condition that results in histotoxic hypoxia is:

Accepted Answer

Histotoxic hypoxia occurs when the tissues are unable to utilize oxygen even though adequate oxygen is delivered. This can occur in cases of cyanide poisoning, where cyanide binds to cytochrome oxidase and disrupts the ability of cells to use oxygen in oxidative phosphorylation. Carbon monoxide poisoning also results in tissue hypoxia but through a different mechanism, as carbon monoxide binds to hemoglobin and prevents the binding of oxygen. Hypoventilation and hypovolemia result in hypoxic hypoxia, where inadequate oxygen is delivered to tissues.

Question 17

Of the following,which device is most likely to transmit bacteria?

Accepted Answer

Large-volume nebulizers are most likely to transmit bacteria because they generate aerosols, which can become contaminated with bacteria if the device is not properly cleaned and maintained. This can lead to the transmission of bacteria to the patient during inhalation therapy.

Question 18

The clinical responses to conditions causing acute hypoxemia include all the following except:

Accepted Answer

Polycythemia is a chronic adaptation to hypoxemia, not an acute response. Acute responses include increased heart rate (tachycardia), increased breathing rate (tachypnea), and elevated blood pressure (hypertension) to improve oxygen delivery to tissues.

Question 19

A nasal cannula can be used to deliver oxygen in all except which of the following situations?

Accepted Answer

A nasal cannula is not effective for treating carbon monoxide poisoning as it does not deliver oxygen at a high enough concentration to displace the carbon monoxide from the hemoglobin molecules. Other forms of oxygen therapy, such as a non-rebreather mask or hyperbaric oxygen therapy, would be more appropriate for treating carbon monoxide poisoning. A nasal cannula can be used for long-term therapy for COPD, to decrease myocardial work, and to treat mild hypoxemia.

Question 20

Oxygen therapy alone will improve PaO₂ levels in all except which of the following conditions?

Accepted Answer

ARDS (Acute Respiratory Distress Syndrome) involves severe inflammation and fluid accumulation in the alveoli, leading to impaired gas exchange that may not be adequately corrected by oxygen therapy alone.

Quiz 12: Therapeutic Medical Gases